Self-loading logger



Jan. 25, 1966 E. E. PARTIN 3,231,119

SELF-LOADING LOGGER Filed Dec. 20, 1963 4 Sheets-Sheet 1 l E w I j &

INVENTOR. EAEL 5'. P.4E7'7/V,

E. E. PARTIN SELF-LOADING LOGGER Jan. 25, 1966 4 Sheets-Sheet 2 Filed Dec. 20, 1963 INVENTOR. [42L 5 4 T/M ,477'0E/VEYS Jan. 25, 1966 E- E. PARTlN 3,231,119

SELF-LOADING LQGGER Filed Dec. 20, 1963 4 Sheets-Sheet 5 Fe O 8 27 26' i w 1 K.

i 20 29 J 'p TE"; g I 30 Q IN VEN TOR BY FIG- 5. jfl g Jan. 25, 1966 E. E. PARTIN SELF-LOADING LOGGER 4 Sheets-Sheet 4 Filed Dec. 20, 1963 INVENTOR. 2427/4 BY WM fl United States Patent 3,231,119 SELF-LOADING LGGGER Earl E. Partin, 413 Ballard St., Ypsilanti, Mich.

Filed Dec. 20, 11963, Ser. No. 332,111' 9 Claims. (Cl. 21439 6) This invention relates to logging vehicles, and more particularly to a wheeled vehicle especially adapted for moving logs from the forest to a road or highway.

A main object" of the invention isfto provide a novel being relatively simple inconstructiombeing easy. to operate, and providing a means for hauling relatively large heavy logs over rough terrain, for example, from the forest to a road or highway.

A further object of the invention is to provide an improved log-hauling vehicle whichis economical to opcrate, whichis durable in construction, which. is easy to load, and which provides excellent traction at all times because of its efficient Weight distribution.

A still further object of'the invention is to provide an improved logging vehicle which can be operated by a single person, which is safe to use, whichcanmake turns without difliculty, and Which'can'operate in almost any.

kind of terrain.

Further objects and advantages of the invention will become apparent from the following descriptionand claims, and from the accompanying drawings, wherein:

FIGUREl is a side elevational view of an improved logging vehicle constructed in accordance with the present invention.

FIGURE 2 is a bottom plan view of the logging vehicle 1 shown in'FIGURE 1.

FIGURE 3 is an enlarged transverse vertical cross sectional view taken substantially'on the line 3 3 of FIG- URE v1.

1O and improvedlog-moving vehicle especially adapted for I hauling logs over relatively rough terrain, the vehicle FIGURE 4 is a cross sectional view taken substantially on the line 4 4 of FIGURES.

FIGURE 5 is'an enlarged cross sectional detail view taken substantially on the line 55 of FIGURE 3.

FIGURE 6 is an enlarged cross sectional view taken substantially on the line 66 of FIGURE4.

FIGURE '7 is an enlarged cross sectional detail view taken substantially on'the line 77 of FIGURE 6.

FIGURE 8 is a horizontal cross sectional view'taken substantially on line 8-3 of FIGURE 3. i

FIGURE 9 is a horizontal cross sectional detail view taken substantially on the line 9-9 of FIGURE 4.

FIGURE 10 is a fragmentary perspective view to a reduced scale, showing the main frame body'and the pivoted under-frame member of the logging vehicle of FIGURES 1 to 9, the pivotal connection being omitted, but the under-frame being arranged in its normal position ,with respect to the main frame body.

Referring to the drawings, 11 generally designates,

a logging tractor constructed in accordance with the present invention. The logging tractor 11' comprises a main frame 12 consisting of a pair of opposing, longitudinally extending channel-shaped side bars 13, 13 formed integrally with a relatively wide cross bar 14 terminating at its opposite ends in'the downwardly facing bearing.

tive wheel axles'2il, and secured to the outer ends of the respective axles are the respective wheels 21, provided with the pneumatic tires 22. i

The wheels21 are of relatively large sizeand the tires 22 are of the type employed on heavy earth-moving vehicles, such as crawler vehicles, or the like, being equipped with heavy ground-engaging lugs to provide traction over rough terrain and under severe conditions, such as in mud or soft ground.

Mounted on the transverse bed portion 14 is a superstructure 23 on. which is supported the conventional tractor engine 24, located at the forward portion of said superstructure, and the operators seat 25 located at the rear portion of the superstructure 23, as shown in FIG- URE 4.

The conventional engine-bearing superstructure 23 includes the transversely extending power output assembly I 2 6 which is driven by the engine 24 .and which is provided at its opposite ends with drive sprockets 27, 27 which are coupledto respective wheel-driving sprockets 23, 28 rigidly secured on the wheel axles 2t),;the sprockets 2? being drivingly coupled to the sprockets 28:.by sprocket chains 29,

The axles 20 are provided with hexagonal portions 30,-

and the Wheel sprockets 28-are provided with hexagonal central apertures engaging on thehexagonal portions 30, so that the sprockets 28 are rigidly coupled to the, axlesmay rotate at different speeds, while; being capable of receiving driving torque from the propeller shaft 32, which is in turn driven by the crankshaft of the engine 24.

Thedriving mechanism between the engine 24 and the wheels 21 is substantially conventional, being thesame as that which is employed on conventional earth-moving equipment and on other vehicles of the tractor type. Thus, the respective driving shaft elements 26', 26' are provided with braking means, namely, conventional brake drum assemblies .34 operated by respective brake levers located at opposite sides of the operators seat 25. As shown in FIGURE 4, each brake drum assembly includes a brake drum 36 secured on the associated shaft 26, and engageable by a brake bandffl surrounding same i and controlled by the associated lever 35through a connecting link rod 38 which tightens the band on the associated drum 36 when the associated lever 35 is pulled by the vehicle operator.

By means of the brake levers 35, either wheel 21 may be braked, allowing the opposite. wheel. to rotate-at a faster speed than the braked wheel, thereby causing the vehicle to turn The levers 35 therefore serveas steering means for the vehicle.

Hingedly connected to and extendingforwardly from the forward end of the main frame 12. is a generally A-shaped auxiliary frame 3%,, to the forward end of which is journ aled a ground-engaging caster Wheel 40. The frame 39 is pivotally connected at 41,41 to the front. corner portions of the main frame 12 on a transverse horizontal axis, whereby theauxiliary frame 3% is swingable vertically on said axis. The auxiliary frame 39 has a cross bar portion 42, and the intermediate portion of the cross bar 42 is connected to the upper front portion of engine 24 by a fluid pressure cylinder and piston assembly 43, the cylinder portion of said assembly being pivotally connected at 44 to the engine .Zdaandlhe piston rod portion of the assembly being pivotally connected at 45 to the cross bar element 42. The cylinder Patented Jan. 25, 1966 43 is connected in the conventional manner through a suitable control valve to the hydraulic fluid pump system of the tractor engine 24, the control valve for the hydraulic cylinder 43 being located adjacent the operators seat 25, so that the operator can control the admission and release of hydraulic fluid under pressure into and from the cylinder 43. Thus, by extending the piston rod of the cylinder 43, the frame 39 may be lowered, whereby the ground-engaging wheel 46 may .act as a stabilizing means to prevent forward tipping of the vehicle when it is traveling in an unloaded condition, for example, when the vehicle is traveling down a slope. The frame 39 will be elevated when the vehicle is traveling under loaded conditions, as illustrated in FIGURE 1.

Designated generally at 46 is an under-frame which underlies the cross member 14 and which is .pivotally connected thereto by a vertical pivot connection 47, said pivotal connection 47 being located substantially at the mid portion of the cross member 14. The under-frame 46 has a rearwardly extending frame portion 48 comprising a pair of parallel bar members 49, 49 connected by cross bar members 50, the narrow frame portion 48 being connected to the [generally rectangular main portion of the under-frame by a pair of rearwardly convergent bar members 51, 51. The main frame 12 includes a transversely extending arcuate end bar 52 which is concentric with the pivotal connection 47 land which is slidably received in a pair of guide sleeves 53, 53 formed integrally with the under-frame 46 and located substantially at the junction [between the rearwardly convergent bar members 51 and the rear side bar elements 49 of the under-frame rear extension 48. The sleeve members 53, 53 receive the arcuate transversely extending cross bar members 52 with sufficient clearance to allow the underframe to swivel [freely around the pivotal connection 47. However, the sleeve members 53, 53 serve as guide means to prevent excessive looseness or vertical movement of the rear portion of the under-frame relative to the cross bar 52.

Journaled to the rear end of the extension 48 is a caster wheel 54 adapted to supportingly engage the ground when the vehicle is traveling in an unloaded condition, limiting rearward tilting of the vehicle.

As shown in FIGURES 6 and 7, suitable roller bearings of the needle type, shown at 60 and 61, may be provided in the sleeve members 63 respectively above and below the arcuate cross bar 52 to smoothly guidethe rear portion of the under-frame 46 as it moves :along the cross bar 52. As shown in FIGURE 7, the roller bearings 60 and 61 have opposite end shaft portions 63, 63 which are pivoted in the respective end walls of the sleeve members 53 to retainthe roller bearings 60 and 61 in proper positions above and below the cross bar 52.

The caster wheel 54 is journaled in a conventional caster bracket assembly 64 which is sw-iveled to the rear end of the under-fratme rear extension 48 so as to be freely rotatable around a vertical axis.

As shown in FIGURE 3, the cross bar portion 14 of the main [fname 12 includes a bottom plate member 66, the pivot connection bolt 47 being fastened'to and depending from the mid portion of said plate member 66. The bolt 47 has an enlarged head 67 which is rotatably received in a cup member 68 formed integrally with the under-frame 46, thereby defining the pivotal connection allowing the under-frame to swivel around the axis of the pivot bolt 47. The under-frame 46 is formed with arcuate guide channels 69, 69 located on opposite sides of and concentric with the pivot bolt 47, said guide channels receiving depending guide pins 70, 70 secured to the plate member 66 and serving as guide means to stabilize the swinging movement of the underframe relative to the nrain frame whenever such movement occurs. The channels 69 may be provided with opposing vertical roller bearings 71 located on opposite sides of and engageable with the depending guide pin elements 70 to provide 4 smooth guiding action between the pins 70 and the arcuate channels 69.

The under-frame 46 includes respective transversely extending cross bar members 72 land 73 located cEorwardly and rearwardly of the arcuate guide channels 69, 69, said cross bar members 72 and 73 being provided with spaced hooks 74. The books are located so that the opposite end portions of a supporting chain 75 can be connected to a pair of hooks 74 on one of the cross barmem'bers 72 or 73 so that the chain can suppiortingly underlie a log 76 and secure the log sub-jacent the under-frame. Thus, a chain 75 may be attached to each of the cross bar members 72 and 73 in the manner above described, so that the log 76 can be secured by both chains and can be thus held against the underside of under-frame 46.

Designated at 77, 77 are a pair of upstanding, substantially vertical fluid pressure cylinders which are resiliently mounted on the main frame 12 on respective plate-like extensions 78, 78 of the cross bar element 14 merging with the side bar elements 13, 13 of the main frame. The plate-like elements 78 are formed with apertures 79, and the cylinders 77 are pivotally mounted for universal tilting action at said apertures 79 in the manner shown in FIG- URES 4 and 9. Thus, outer rings 86 are rigidly secured around the margins of the apertures 79 and the lower end portions of the cylinders, 77 are pivoted to inner rings 81, said inner rings 81 being in turn pivoted within the outer rings 80, the pivotal connections of the cylinders 77 to the inner rings being displaced 90 from the pivotal connections of the inner rings 81 tothe outer rings 80. The upper portions of the cylinders 77 are received in ringshaped brackets 82 secured to opposite sides of the engine 24, the cylinders being biased toward centered positions in said brackets by coiled springs 83 connected to the cylinders 77 and extending radially outwardly therefrom, the outer ends of the springs being connected to the brackets 82, as shown in FIGURE 8. Any suitable number of springs may be employed, for example four springs spaced 90 from each other, as illustrated in FIG- URE 8.

The upstanding cylinders 77 contain pistons 84 which extend through the apertures 79 and which are provided at their lower ends with hooks 85 pivotally connected thereto. The lower end portions of the'piston rods 86 extend slidably and sealingly through the bottom walls or" the cylinders 77. The cylinders are, operated by fiuid pressure from the hydraulic fluid pump of the tractor motor 24 through suitable valve means located Within convenient reach of the vehicle operator, said valve means being provided with operating levers 87, as shown in FIG- URE 4, to control the upward and downward movement of the piston rods 86.

The cylinders 77 are located over open portions of the under-frame 46, for example, portions located between the arcuate channel members 69 and the side bar elements 89 of the under-frame. The books 85 are located to receive the opposite end portions of a lifting chain which may be engaged beneath a log 76, whereby the cylinders 77 may be employed to lift the log to a position engaging the underside of the under-frame, after which the supporting chain 75 may be engaged around the log and secured to hooks 74 in the manner above described.

In attaching a log 76 to the vehicle, the vehicle is first moved to a position overlying the log, with the front frame 39 being elevated, the rear caster wheel 54 being either disposed laterally of the log or engaged thereon. The forward portion of the log is then elevated into engagement with the underside of the under-frame by means of the hydraulic cylinders 77, 77, in the manner above described, namely, by engaging a chain under the log and securing the chain to the hooks 85, 85, after which the pistons 84 are elevated in the cylinders 77, causing the log to be lifted so that it may be brought substantially into contact with the underside of under-frame 46. Thereafter, the forward portion of the logis secured to the untier-frame by means of chains 75, 75, fastened on hooks 74. The elevating pistons 84 may then be lowered, to allow the elevating chains to be removed. The log can then then be hauled by means of the vehicle to its intended destination. It will be noted that when the log is elevated substantially into contact with the underside of under-frame 46, the rear extension 48 of the under-frame is elevated, since said rear extension is angled with respect to the generally rectangular main forward portion of the under-frame, as is clearly shown in FIGURE 1. The extension 48 extends at a sufliciently large angle with respect to the plane of the generally rectangular forward portion of the under-frame to insure that the caster wheel 54 will :be elevated clear of the log 76 when the log is brought up against the underside of the under-frame by the action of the hydraulic elevating cylinders 77, 77. Therefore, due to the inclination of the rear extension 48 of the under-frame, the log will underlie said extension when it is in loaded position, and the caster wheel 54 will be held clear of the log. In said loaded condition of the log, the major portion thereof extends rearwardly of the vehicle and serves as a weighting means to hold the vehicle in the inclined position thereof illustrated in FIG- URE l, to thus prevent forward tipping of the vehicle and to provide efficient weight distribution, with a substantial portion of the weight of the log acting on the vehicle to provide a high degree of traction for the wheels 21.

It will be noted that the forward portion of the log 76 is secured to the underside of under-frame 46 with the major portion of the log extending rearwardly of the vehicle and engaging the ground. The under-frame is free to swivel at the pivotal connection 47 relative to the main frame 12 so that the logging tractor Ill can be readily steered by selectively braking the respective wheels 21, 21 in the manner above described, whereby to alter the direction of movement of the forward portion of the log 76 and to thereby haul the log around turns, as required.

When the log has been hauled to its intended destination, it can be released by following a procedure reverse to that above described, namely, by first engaging a sup porting chain around the log with the end portions of the chain attached to the hooks 85, elevating said hooks 85 to take the load off the chain 75, detaching said chain 75, and then lowering the hooks 85, thus allowing the forward portion of the log to be lowered to the ground.

The universal connection of the elevating cylinders 77 to the plate-like members 78 allows said cylinders to adjust themselves to proper positions aligned with the hooks 85 to allow said hooks to apply lifting force to the supporting chain secured beneath a log over a wide range of positions of the log, namely, under conditions where the is inclined or askew relative to the under-frame 46.

While a specific embodiment of an improved logging tractor has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. A logging tractor comprising a main frame, a pair of main supporting wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said wheels, an under-frame pivoted to said main frame and extending longitudinally thereof, said under-frame being provided with a portion extending a substantial distance rearwardly of said main frame, a caster wheel journaled to the end of said rearwardly extending portion, a pair of upstanding vertical fluid pressure cylinders mounted on opposite sides of said main frame and having vertically movable pistons therein, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position subjacent the under-frame, a supporting chain adapted to engage beneath the log, and

6 means to connect the opposite ends of said supporting chain to the under-frame.

2. A logging tractor comprising a main frame, a pair of main supporting Wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivin-gly connecting said engine to said wheels, an under-frame pivoted to said main frame for rotation on a vertical axis and extending longitudinally thereof, said under-frame being provided with a portion extending a substantial distance rearwardly of said main frame, a caster Wheel journaled to the end of said rearwardly extending portion, a pair of upstanding vertical fluid pressure cylinders mounted on opposite sides of said main frame and having vertically movable pistons there-in, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position subjacent the under-frame, a supporting chain adapted to engage beneath the log, means to connect the opposite ends of said supporting chain to the under-frame, an auxiliary caster frame pivoted to the forward end of said main frame and being provided with a ground-engaging wheel, and fluid pressure-operated means connected between said auxiliary caster frame and the main frame for raising and lowering said auxiliary caster frame.

3. A logging tractor comprising a main frame, a pair of main supporting wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said wheels, an under-frame pivoted to said main frame for rotation on an axis perpendicular to said main frame and extending longitudinally of said main frame, said under-frame being provided with a portion extending a substantial distance rearwardly of said main frame, a caster wheel journaled to the end of said rearwardly extending portion, a transversely extending guide bar on the rear end of said main frame, guide sleeve means on the under-frame slidably receiving said guide bar, a pair of upstanding vertical fluid pressure cylinders mounted on opposite sides of said main frame and havingvertically movable pistons therein, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position subjacent the under-frame, a supporting chain adapted to engage beneath the log, and means to connect the opposite ends of said supporting chain to the underframe.

4. A logging tractor comprising a main frame, a pair of main supporting wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said wheels, an under-frame pivoted to said main frame for rotation on an axis perpendicular to said main frame and extending longitudinally of said main frame, said under-frame being provided with a portion extending a substantial dis tance rearwardly of said main frame, a caster wheel journaled to the end of said rearwardly extending portion, a transversely extending guide bar on the rear end of said main frame, guide sleeve means on the under-frame slidably receiving said guide bar, a pair of upstanding vertical fluid pressure cylinders mounted on opposite sides of said main frame and having vertically movable pistons therein, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position subjacent the under-frame, a supporting chain adapted to engage beneath the log, means to connect the opposite ends of said supporting chain to the under-frame, an auxiliary caster frame pivoted to the forward end of said main frame and being provided with a ground-engaging wheel, and fluid pressure-operating means connected between said auxiliary caster frame and the main frame for raising and lowering said auxiliary caster frame.

5. A logging tractor comprising a main frame, a pair of main supporting Wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said wheels,

an under-frame pivoted to said main frame for horizontal rotation and extending longitudinally of said main frame, said under-frame being provided with a port-ion extending a substantial distance rearwardly of said main frame, a caster wheel journaled to the end of said rearwardly extending portion, a transversely extending arcuate guide bar on the rear end of said main frame, guide sleeve means on the under-frame slidably receiving said guide bar, a pair of upstanding vertical fluid pressure cylinders pivotally mounted on opposite sides of said main frame and having vertically movable pistons therein, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position adjacent the under-frame, a supporting chain adapted to engage beneath the log, and means to connect the opposite ends of said supporting chain to the under-frame.

6. A logging tractor comprising a main frame, a pair of main supporting wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said wheels, an under-frame pivoted to said main frame for rotation on an axis perpendicular to said :main frame, said underframe extending longitudinally of the main frame and being provided with a portion extending a substantial distance rearwardly of said main frame, a caster wheel journaled to the end of said rearwardly extending portion, a pair of upstanding vertical fluid pressure cylinders pivotally mounted on opposite sides of'said main frame and having vertically movable pistons therein, means resiliently biasing said cylinders toward vertical positions, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position subjacent the under-frame, a supporting chain adapted to engage beneath the log, and means to connect the opposite ends of said supporting chain to the under-frame.

7. A logging tractor comprising a main frame, a pair of main supporting wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said wheels, an under-frame pivoted to said main frame for rotation on an axis perpendicular to said main frame and extending longitudinally of the main frame, said underframe being provided with a portion extending a substantial distance rearwardly of said main frame, a caster wheel journaled to the end of said rearwardly extending portion, a transversely extending arcuate guide bar on the rear end of said main frame concentric with the pivotal connection of the under-frame to the main frame, guide sleeve means on the under-frame slidably receiving said guide bar, a pair of upstanding vertical fluid pressure cylinders pivotally mounted on opposite sides of said main frame and having vertically movable pistons therein, means resiliently biasing said cylinders toward vertical positions, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position subjacent the under-frame, a supporting chain adapted to engage beneath the log, means to connect the opposite ends of said supporting chain to the underframe, an auxiliary caster frame pivoted to the forward end of said main frame and being provided with a ground-engaging wheel, and fluid pressure-operated means connected between said auxiliary caster frame and the main frame for raising and lowering said auxiliary caster frame.

8. A logging tractor comprising a main frame, a pair of main supporting wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said Wheels, an under-frame pivoted to said main frame for rotation on an axis perpendicular to said main frame, a pair of upstanding fluid cylinders mounted on opposite sides of said main frame and having pistons therein, means for connecting a transverse elevating chain to the lower ends of said pistons for raising a log to a position subjacent the under-frame, a supporting chain adapted to engage beneath the log, and means to connect the opposite ends of said supporting chain to the under-frame.

9. A logging tractor comprising a main frame, a pair of main supporting wheels journaled to opposite sides of said main frame, an engine mounted on said main frame, means drivingly connecting said engine to said wheels, an underframe pivoted to said main frame and having a main portion extending longitudinally of the main frame and a rear extension angled upwardly relative to said main portion and extending a substantial distance rearwardly of said main frame, a caster wheel journaled to the end of said reartextension, chain-supporting means mounted on opposite sides of said main frame, means for elevating at least one of said chain-supporting means, whereby a chain connected to said chain-supporting means and engaged beneath a log will raise the log to a position subjacent the underframe, a supporting chain adapted to engage beneath the log, and means to connect the opposite ends of said last-named chain to the underframe.

No references cited.

GERALD M. FORLENZA, Primary Examiner.

A. I. MAKAY, Assistant Examiner. 

1. A LOGGING TRACTOR COMPRISING A MAIN FRAME, A PAIR OF MAIN SUPPORTING WHEELS JOURNALED TO OPPOSITE SIDES OF SAID MAIN FRAME, AN ENGINE MOUNTED ON SAID MAIN FRAME, MEANS DRIVINGLY CONNECTING SAID ENGINE TO SAID WHEELS, AN UNDER-FRAME PIVOTED TO SAID MAIN FRAME AND EXTENDING LONGITUDINALLY THEREOF, SAID UNDER-FRAME BEING PROVIDED WITH A PORTION EXTENDING A SUBSTANTIAL DISTANCE REARWARDLY OF SAID MAIN FRAME, A CASTER WHEEL JOURNALLED TO THE END OF SAID REARWARDLY EXTENDING PORTION, A PAIR OF UPSTANDING VERTICAL FLUID PRESSURE CYLINDERS MOUNTED ON OPPOSITE SIDES OF SAID MAIN FRAME AND HAVING VERTICALLY MOVABLE PISTONS THEREIN, MEANS FOR CONNECTING A TRANSVERSE ELEVATING CHAIN TO THE LOWER ENDS OF SAID PISTONS OF RAISING A LOG TO A POSITION SUBJACENT THE UNDER-FRAME, A SUPPORTING CHAIN ADAPTED TO ENGAGE BENEATH THE LOG, AND MEANS TO CONNECT THE OPPOSITE ENDS OF SAID SUPPORTING CHAIN TO THE UNDER-FRAME. 